A persistent untranslated sequence within bacteriophage T4 DNA topoisomerase gene 60.

A 50-nucleotide untranslated region is shown to be present within the coding sequence of Escherichia coli bacteriophage T4 gene 60, which encodes one of the subunits for its type II DNA topoisomerase. This interruption is part of the transcribed messenger RNA and appears not to be removed before translation. Thus, the usual colinearity between messenger RNA and the encoded protein sequence apparently does not exist in this case.

Invertebrate vasopressin/oxytocin homologs. Characterization of peptides from Conus geographus and Conus straitus venoms.

The vasopressin-oxytocin family of peptides is of very ancient lineage, found in organisms as diverse as hydra and man. Although these peptides have been intensively studied in vertebrates, the presumably more extensive invertebrate series was defined primarily by immunological methods. In this report, we describe the purification and structures of two peptides of the vasopressin-oxytocin family from molluscs ("Conopressins"), which were found in the venom of fish-hunting marine snails of the genus Conus.

Neuronal calcium channel antagonists. Discrimination between calcium channel subtypes using omega-conotoxin from Conus magus venom.

The omega-conotoxins from the venom of fish-hunting cone snails are probably the most useful of presently available ligands for neuronal Ca channels from vertebrates. Two of these peptide toxins, omega-conotoxins MVIIA and MVIIB from the venom of Conus magus, were purified. The amino acid sequences show significant differences from omega-conotoxins from Conus geographus.

Relationship of organ lipoprotein lipase activity and ketonuria to hypertriglyceridemia in starved and streptozocin-induced diabetic rats.

Although lipoprotein lipase (LPL) is believed to be rate limiting in the catabolism of triglyceride-rich lipoproteins, LPL activity has not correlated with plasma triglyceride concentrations in experimental rat diabetes. To gather more information about this enzyme system in diabetes, LPL activities were measured in representative tissues from control and streptozocin-induced diabetic rats fed fat-free chow and in 48-h-starved animals. The DNA content of each tissue was determined so that LPL activity could be expressed in a way that was unaffected by tissue wasting.

Peptide neurotoxins from fish-hunting cone snails.

To paralyze their more agile prey, the venomous fish-hunting cone snails (Conus) have developed a potent biochemical strategy. They produce several classes of toxic peptides (conotoxins) that attack a series of successive physiological targets in the neuromuscular system of the fish. The peptides include presynaptic omega-conotoxins that prevent the voltage-activated entry of calcium into the nerve terminal and release of acetylcholine, postsynaptic alpha-conotoxins that inhibit the acetylcholine receptor, and muscle sodium channel inhibitors, the mu-conotoxins, which directly abolish muscle action potentials.

Conus geographus toxins that discriminate between neuronal and muscle sodium channels.

We describe the properties of a family of 22-amino acid peptides, the mu-conotoxins, which are useful probes for investigating voltage-dependent sodium channels of excitable tissues. The mu-conotoxins are present in the venom of the piscivorous marine snail, Conus geographus L. We have purified seven homologs of the mu-conotoxin set and determined their amino acid sequences, as follows, where Hyp = trans-4-hydroxyproline.

A toxic thionin from Pyrularia pubera: purification, properties, and amino acid sequence.

A low-molecular-weight cytotoxic protein has been purified from Pyrularia pubera Michx. (Santalaceae). By comparison with the behavior of proteins of known molecular weight during Sephadex G-75 gel filtration and denaturing electrophoresis, a molecular weight of somewhat less than 6000 is indicated.

Structural characterization of the isoforms of neonatal and adult rat liver metallothionein.

Metallothionein was purified from the livers of adult and neonatal rats. The complete amino acid sequences of isoforms I and II of Cd-induced adult metallothionein were determined by automated Edman degradation of CNBr and tryptic peptides of carboxymethylated proteins. Both isoproteins contain 61 residues, but differ at 12 of those positions.